Examine source code of ShieldBlock

{
  "manifest_version": 2,
  "name": "ShieldBlock",
  "version": "1.5resigned1",
  "description": "Blocks distracting websites with exceptions to particular pages on the site",
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "<all_urls>",
    "storage"
  ],
  "background": {
    "scripts": [
      "background/background.js"
    ]
  },
  "applications": {
    "gecko": {
      "strict_min_version": "56.0a1",
      "id": "{e486180e-7b55-46b6-a868-aef4b0bde2c9}"
    }
  },
  "browser_action": {
    "default_title": "ShieldBlock",
    "default_icon": "icons/shield.svg",
    "default_popup": "popup/shieldblock.html"
  }
}